Pea compression is
optional, at current level of implementation are
defined only following levels: PCOMPRESS0 (store only, no compression),
and PCOMPRESS1..3 based on deflate (reference zlib's compres/uncompres
algorithm code), respectively at compression level 3, 6 and 9.

PEA format security model
acts
at 3 levels: objects (input files and folders sent to .pea archive),
volumes (output archive file that can be spanned to user defined size)
and streams (the actual output data stream that is formed by multiple
input files and can be written written to multiple output volumes);
each one of those levels can
be omitted as needed by the user.

Volume level integrity check is communication
oriented and allow to discard single corrupted volumes in order to
minimize, in case of error, the retransmission overhead;

Current implementation allows same Checksum and
Hash algorithms featured by Object level check

Stream level check offers wide choice of
algorithms
up to authenticated encryption, protecting privacy and authenticity of
a group of objects sharing same security needs, including tags
generated by object level checks;

Arbitrarily sized
volume
spanning allows the archive to be splitted in volumes of arbitrary
size, with the only constrain of volumes being at least 10 byte bigger
than volume control tag to allow passing (through archive's header)
minimum needed information to the extraction application.

PEA file format standard, as defined in version 1 revision 1
specification, can
store a single stream containing unlimited objects, each up to 2^64
byte
in size; current Pea executable supports 1.1 file format
specifications (practically, archives are memory and filesystem-limited
rather than format limited) and is featured starting from PeaZip 6.0.1
release, previous PeaZip releases supporting PEA 1.0 format revision.

PEA 2.0 file format specifications extend the concepts behind PEA 1.x
file format and can store an unlimited number of stream, but the format
is not actually supported by current Pea archiving utility.

Here, a brief table
of
features and limitations applying to file format and to current
implementation:

Feature

PEA
file format

Current
implementation

Archive

Max
archive size

unlimited, no limit is set by
the format design for maximum archive size, only filesystem size
limitations applies

up to 999999 volumes of
2^64-1
byte each; using 128 bit block encryption it would be safe not to
encrypt more than 2^64 byte with same key, better staying one or more
orders of magnitude below

For a more complete
explanation and discussion of the pea format
specifications please see the documentation about Pea archive format
design (.pdf).

When
it is recommended to use PEA format: it is a good choice when
it is needed to guarantee confidentiality (data cannot be accessed
without password), integrity, and autenticity - data can only be
modified by recipient knowing the password, as data is subject to
password-dependent, cryptographically strong verification.